Rupert Dempf

Mini- and Micro-screws for Temporary Skeletal Anchorage in Orthodontic Therapy

Objective:Mini- and micro-screws are of increasing interest in orthodontic therapy in cases where maximum anchorage is requested. In this study we aimed to identify the criteria that influence the clinical success of micro-implants.Material and Methods:239 micro-implants were inserted for skeletal anchorage in 85 patients undergoing orthodontic therapy. The survival rates of the first 133 implants were analyzed and those results were later applied in treating subsequent patients.Results:In so doing, we were able to reduce the loss rate from 23% to 5%. Using thicker implants on the labial side of the lower jaw and the lingual side of the upper jaw was an important factor in reducing failure rates. We found the lower jaw’s lingual side to be an inadequate region for inserting micro-implants. Thinner micro-implants were selected for the upper jaw’s labial side.Conclusion:By following these guidelines, practitioners may find mini- and micro-screws to offer reliable orthodontic support.ZusammenfassungZiel:Mini- und Mikroschrauben sind von zunehmendem Interesse als Ergänzung der kieferorthopädischen Therapie, um maximale Verankerung zu erreichen. Ziel der vorliegenden Studie war es, Kriterien herauszuarbeiten, die die Erfolgsrate der Miniimplantate beeinflussen.Material und Methodik:Bei 85 Patienten wurden insgesamt 239 Miniimplantate zu kieferorthopädischen Zwecken inseriert. Die Ergebnisse der ersten 133 inserierten Implantate wurden analysiert und die gewonnenen Erkenntnisse auf alle folgenden Patienten angewandt.Ergebnisse:Es gelang hierdurch, die Verlustrate von 23% auf 5% zu senken. Ausschlaggebend für die Verringerung der Misserfolge war, dass im Unterkiefer vestibulär sowie im Oberkiefer palatinal möglichst dicke Miniimplantate benutzt wurden. Eine Implantation im lingualen Bereich des Unterkiefers wurde nicht mehr durchgeführt; auf der vestibulären Seite des Oberkiefers wurden dünnere Mikroschrauben gewählt.Schlussfolgerung:Bei Beachtung dieser Auswahlkriterien konnte mit Mini- und Mikroschrauben eine verlässliche Ergänzung der kieferorthopädischen Mechanotherapie erreicht werden.

Reliability and validity of a modified lateral cephalometric analysis for evaluation of craniofacial morphology and growth in patients with clefts.

In previous intercenter studies on craniofacial morphology in patients with unilateral cleft lip and palate, probable surgical-induced changes in mandibular morphology and spatial position related to posterior vertical maxillary morphology were identified by our group. These changes could not be detected in other cephalometric cleft studies because posterior vertical maxillary height and vertical mandibular ramus length were not measured simultaneously. This study presents a modified digital lateral cephalometric hard and soft tissue analysis (Onyx Ceph software, version 2.5.6.; Image Instruments GmbH, Chemnitz, Germany) to evaluate craniofacial morphology and growth patterns in patients with clefts. Forty controls without clefts were used to evaluate the accuracy, reliability, and validity of this analysis for future cleft research. Measurement error according to the method of Bland and Altman was less than 1.00° and 1.00 mm, whereas squared correlation coefficients (r2) according to the method of Sackett et al showed a high reliability. Method comparison tests according to the method of Bland and Altman clearly showed that the modified digital cephalometric analysis (“test”) was valid for future cleft research compared with the “gold standard” (conventional cephalometry).

Erfahrungen mit der Distraktionsosteogenese bei der Therapie schwerer peripherer Atemwegobstruktionen im Säuglings- und Kleinkindalter

Kinder mit kraniofazialen Fehlbildungen neigen in besonderem Maß zu obstruktiven Atemwegstörungen. Eine besondere Rolle spielen Anomalien, die mit einer Unterentwicklung oder Rücklage des Unterkiefers einhergehen. Hierbei liegt der Zungengrund der Rachenhinterwand an und verlegt so die Luftwege. Durch Anwendung der Distraktionsosteogenese können eine Verlängerung der unterentwickelten Mandibula und dadurch eine Ventralisierung der Zunge erreicht werden. Drei kleine weibliche Patienten im Alter von 7–15 Monaten mit schweren syndromalen Erkrankungen und peripheren Atemwegobstruktionen bei mandibularer Mikrognathie wurden durch Verlängerung der Mandibula mittels Kallusdistraktion behandelt. Wegen Schluckunfähigkeit war bei allen 3 Kindern eine Gastrostomie bzw. eine permanente Nasogastralsonde angelegt worden. Bei der ersten kleinen Patientin, die schon kurz nach der Geburt tracheotomiert wurde, konnten 10 Tage nach Beginn der Distraktion Schluckversuche durchgeführt werden. Vor der geplanten Dekanülierung muß jedoch noch die Abtragung umfangreicher Trachealgranulationen erfolgen. Bei der 2. Patientin konnte am 6. Tag der Distraktion der Nasopharyngealtubus entfernt und auf eine geplante Tracheotomie verzichtet werden. Beim 3. Fall bildete sich eine therapierefraktäre Schlafapnoe unter der Distraktion völlig zurück. Unsere Erfahrungen zeigen, daß die Distraktionsesteogenese zur Behandlung obstruktiver Atemstörungen in Verbindung mit Minderentwicklungen des Unterkiefers auf der Grundlage einer eingehenden interdisziplinären Untersuchung mit genauer Lokalisation des Atemweghindernisses ein wertvolles alternatives Therapiekonzept darstellt. Children with craniofacial malformations are at special risk for the development of peripheral airway obstruction. The problems are magnified in patients with retroposition or hypoplasia of the mandible. In these cases, the base of the tongue is posteriorly displaced, hereby decreasing the airway diameter. By application of distraction osteogenesis the mandible can be lengthened to move the base of the tongue forward and open the airway. Three female patients aged between 7, 11, and 15 months suffering from peripheral airway obstruction caused by mandibular hypoplasia were treated by gradual distraction. All of them had a gastrostomy or a nasogastral tube in place, respectively, due to severe nutrition problems. In the youngest patient tracheostomy was performed shortly after birth and was already planned in the 15-month-old child, who had received a permanent nasopharyngeal tube. The 11-month-old child suffered from severe refractory sleep apnea. Exercises in oral feeding were possible in the youngest patient after 10 days of distraction. In the oldest one, the airway tube was removed on the six day of distraction and, thus, tracheotomy was successfully avoided. In the 11-month-old child apneic events a rapidly decreased. Our experience suggests that distraction osteogenesis after careful preoperative evaluation can be successfully performed for the treatment of peripheral airway obstruction in patients with selected craniofacial anomalies.

Craniofacial reconstruction by transport distraction osteogenesis: corticotomy versus osteotomy--an experimental study.

Transport osteogenesis is a modified technique of callus distraction appropriate for the reconstruction of extended osseous defects of long or flat bones. The aim of this study was to determine the regenerative potential of this technique related to the degree of mobilization of the transport segment. In 10 adult sheep, critically sized defects of the calvaria were treated by gradual movement of a transport segment consisting of calvarial bone. The transport segments were either corticotomized (n = 5) or osteotomized (n = 5). The latency period was 5 days; the rate of distraction was 1 mm/d, extended for approximately 40 days. The consolidation period was 28 days. Specimens were investigated by conventional radiography, computed tomography scans, immunofluorescence, and histological examination. In both groups, transport osteogenesis resulted in a complete closure of the defect. The volume and thickness of newly formed bone at the defect site did not differ significantly between the groups, nor did the extent of vascularization. Bone formation and remodeling occurred during the entire period of distraction and consolidation. Osteotomized transport segments became smaller during distraction, whereas the volume of corticotomized segments remained relatively constant. In conclusion, transport osteogenesis resulted in reliable closure of extended skull defects in adult organisms; corticotomy and osteotomy of the transport segment led to a similar extent of bone formation.

Nasalance measures in German-speaking cleft patients.

The purpose of this study was to evaluate nasalance measures in German-speaking patients with different types of repaired cleft lip and palate and to find out if significant nasalance gender differences exist in the different cleft groups. A total of 125 German-speaking cleft patients (74 male and 51 female) were included in this study: 18 patients with isolated unilateral cleft lip (UCL; mean age: 13.00 ± 2.03 years), 66 patients with complete unilateral cleft lip and palate (UCLP; mean age: 14.80 ± 3.45 years), 25 patients with isolated cleft palate (CP; mean age: 14.60 ± 3.48 years), and 16 patients with complete bilateral cleft lip and palate (BCLP; mean age: 14.30 ± 3.61 years). Nasalance data were collected and computed using the NasalView hardware/software system (Fa. Tiger Electronics, Seattle, WA). Speech stimuli according to a modified Heidelberg Rhinophonia Assessment Form (sustained vowels “a,” “e,” “i,” “o,” and “u”; oral and nasal sentences; and three oral-nasal reading passages) were used to obtain nasalance scores. Nasalance distance and ratio were also calculated for the oral and nasal sentences and for one of the oral-nasal reading passages. Unpaired t tests showed no significant gender nasalance differences in each cleft group. Analysis of variance showed no significant differences in mean nasalance distance and ratio. For the nasal sentence, a significant difference (P = 0.032) in mean nasalance scores was found between the UCL and UCLP groups.

Immunhistochemische Lokalisation des Insulin-like growth factor-binding protein-6 in der Kopfregion der Maus

Hintergrund. Das Insulin-like growth factor-System (IGF-System) ist ein wichtiger Regulator für Wachstum und Differenzierung von Zellen. Die mitogenen und metabolischen Wirkungen der IGFs werden durch eine Familie von 6 hochaffinen Bindungsproteinen (IGFBP) moduliert. IGFBP-6 bindet IGF II mit höherer Affinität als alle anderen IGFBPs. Methode. In dieser Studie wurden spezifische Antikörper gegen murines rekombinantes IGFBP-6 verwendet, um IGFBP-6 in der späten Embryogenese und an neugeborenen Mäusen durch Immunhistochemie in der Kopfregion zu lokalisieren. Ergebnisse. Immunreaktivität konnte im Mundhöhlen- und Nasenepithel, den Zahn-, Skelettmuskel- und Glandula submandibularis-Anlagen sowie bei der enchondralen Ossifikation und in Osteoklasten nachgewiesen werden. Background. The insulin-like growth factor (IGF) system is an important regulator of cell growth and differentiation. The mitogenic and metabolic activities of IGFs are modulated by a family of six high-affinity IGF binding proteins (IGFBPs). IGFBP-6 is unique among the IGFBPs in its preferential binding of IGF II. Methods. In this study, specific antibodies against recombinant mouse IGFBP-6 generated in chicken were used to localize IGFBP-6 by immunohistochemistry in the head region during late embryonic and newborn mice. Results. Immunoreactivity was detected in oral and nasal mucosa, tooth-forming anlage, anlage of skeletal muscle, anlage of submandibular glands, enchondral ossification, and osteoclasts.